The President's message read:

"On behalf of the American people, I condemn in the strongest terms what appears to be a horrific terrorist attack in Nice, France, which killed and wounded dozens of innocent civilians. Our thoughts and prayers are with the families and other loved ones of those killed, and we wish a full recovery for the many wounded. I have directed my team to be in touch with French officials, and we have offered any assistance that they may need to investigate this attack and bring those responsible to justice. We stand in solidarity and partnership with France, our oldest ally, as they respond to and recover from this attack.

On this Bastille Day, we are reminded of the extraordinary resilience and democratic values that have made France an inspiration to the entire world, and we know that the character of the French Republic will endure long after this devastating and tragic loss of life.

Russian President Vladimir Putin on Friday expressed its solidarity with France, describing it as a "barbaric act" and calling for a continued "fight against terrorism".

"Russia is in solidarity with the French people that day difficult," said the Russian president in a telegram addressed to French President Francois Hollande, according to the Kremlin spokesman Dmitry Peskov.

The full statement read: “I want to express the Spanish government’s condolences following last night’s brutal terrorist attack in Nice. Today, we feel the immense pain that afflicts our neighbours as if it were our own. It’s a pain that all good people feel as potential victims of barbarity, senselessness and the most absolute disregard for human life. I’d like to reiterate once again our loyal and sincere commitment to our French neighbours, partners, allies and friends.

“Spain will give its full co-operation to France to help find, pursue and punish terrorists and those who support and protect them. We know that no one is completely safe from atrocities like last night’s, which, until recently, would have been unimaginable. We are facing a global threat that demands a global and integrated response. And Spain, which has suffered deeply from terrorist, is present and active in that global response.”

Anne Hidalgo, Mayor Of Paris, said: "On behalf of Parisians, all our more fraternal support to the nice people. Our cities are United."

Turkish President Recep Tayyip Erdogan described the attack as "inhumane."

The full statement read:

"I strongly condemn the inhumane attack that took place during Bastille Day celebrations in Nice, France. I keep those who lost their lives in yesterday's attack in my thoughts and prayers and wish a speedy recovery to the wounded. On behalf of the Turkish people, I would like to offer my condolences to the victims' families and the French people.

Having suffered a number of terror attacks ourselves, we understand what France and the French people are going through today. This barbaric act, which appears to be a terror attack, highlights the necessity of fighting terrorism in a determined and consistent manner.

We expect those who act inconsistently in the face of terror to draw necessary lessons from the most recent attack in France. For terrorist groups, there is no difference between Turkey and France, Iraq and Belgium, and Saudi Arabia and the United States.

Terrorism has no religion, race or nationality. And the perpetrators of this bloodthirsty attack have nothing to do with humanity. In fact, there is no room for these barbarians in this world -- nor should there ever be.

Once again, I would like to express our deep sadness and solidarity with the people of France. On this difficult day, Turkey stands together with France and the French people.

I would like to offer my condolences to President François Hollande of France and the French people.”

British Prime Minister Theresa May says she is "shocked and concerned" by the attack.

The statement read: "I am shocked and saddened by the horrifying attack in Nice last night. Our hearts go out to the French people, and to all those who have lost loved ones or been injured.

While the full picture is still emerging, it seems that at least 80 people are feared dead and many others have been injured. These were innocent victims enjoying a national celebration with their friends and families.

We are working urgently to establish whether any British nationals were caught up in the attack. Our Ambassador is travelling to Nice today with consular staff and they will be doing all they can to help anyone affected.

I have asked my Deputy National Security Adviser to chair a COBR meeting of senior officials to review what we know and what we can do to help.

And I will speak to President Hollande today and make clear that the United Kingdom stands shoulder to shoulder with France today as we have done so often in the past.

If, as we fear, this was a terrorist attack then we must redouble our efforts to defeat these brutal murderers who want to destroy our way of life.

We must work with France and our partners around the world to stand up for our values and for our freedom."

Ban Ki-moon, the Secretary-General of the United Nations, says he hopes those responsible for the massacre will be "rapidly identified and brought to justice."

The likely Democratic presidential nominee Hilary Clinton said in a statement: "Once again, it appears that terrorists have struck at one of our closest allies in Europe, attacking families celebrating the history and culture of their country on Bastille Day. Every American stands in strong solidarity with the people of France, and we say with one voice: we will not be intimidated."

The full statement read: "On this special day for our country, where we celebrated our national day, France has once again been struck in his heart.

Through Nice, its residents, its tourists and the famous Promenade des Anglais, France has been directly targeted last night by Islamist terrorism.

Like all the French, we are struck with terror and immense emotion in response to this mass murder, which affects whole families and their children and which plunges a whole nation, an entire area, a city and its inhabitants into mourning.

My thoughts go first to the victims who were cowardly killed, to their families, the injured, but also to our law enforcement, emergency services and to all the politicians who have fully rallied together throughout this long night.

In the face of terrorist barbarity and individuals willing to do anything to attack France and the French, it is essential to extend the state of emergency and to use it fully to ensure the safety and protection of the French. We are in a war that will last, with a threat that is constantly renewing itself. Adapting and constantly strengthening our measures to combat Islamist terrorism remains a top priority. An exceptional steadfastness and vigilance of every moment, and for a long time, will be needed. Nothing can be as before."